Another blaze in Riverside, the "Gifford fire" was contained, after it burnt 151 hectares, Scribner said.

In San Diego County, 250 firefighters battled a separate blaze near the US Marine Corps at Camp Pendleton, in San Diego county, which was nearly 85 per cent contained, said camp spokesman Sergeant Jim Goodwin.

More than 728 hectares were burnt in the fire, which began midday Sunday, said Goodwin.

The months of high temperatures and dry spell which California authorities call the "fire season," began on Monday. An abundance of dead wood, after droughts and an invasion of beetles, provided the kindling.

Late yesterday, a man was detained for allegedly having set one fire, but the causes of the rest are unknown.

In October, nearly 15,000 firefighters fought the deadliest fires California has faced, in which 24 died.